FOOD!!!
What was the pup on before you got him? It's important to keep them on the same food, and at the least, get some of what was being used to gradually mix into what you're going to be using. There are a lot of different-and good- foods out there. The best advice is to read up on as many as you can and try the ones that you feel the most comfortable with. I personally use Canidae. It's never let me down, folks can't believe the sheen on my dogs and the muscle build on them. But, go to www.thepetcenter.com and read what they have to say about each ingrediant and the importance of them, after you find out what was previously fed to your pup.